Jeff L. Fidler

Prospective Comparison of State-of-the-Art MR Enterography and CT Enterography in Small-Bowel Crohn's Disease

OBJECTIVE The objective of our study was to prospectively obtain pilot data on the accuracy of MR enterography for detecting small-bowel Crohns disease compared with CT enterography and with a clinical reference standard based on imaging, clinical information, and ileocolonoscopy. SUBJECTS AND METHODS The study group for this blinded prospective study was composed of 33 patients with suspected active Crohns ileal inflammation who were scheduled for clinical CT enterography and ileocolonoscopy and had consented to also undergo MR enterography. The MR enterography and CT enterography examinations were each interpreted by two radiologists with disagreements resolved by consensus. The reports from ileocolonoscopy with or without mucosal biopsy were interpreted by a gastroenterologist. The reference standard for the presence of small-bowel Crohns disease was based on the final clinical diagnosis by the referring gastroenterologist after reviewing all of the available information. RESULTS All 33 patients underwent CT enterography and ileocolonoscopy, 30 of whom also underwent MR enterography. The sensitivities of MR enterography and CT enterography for detecting active small-bowel Crohns disease were similar (90.5% vs 95.2%, respectively; p = 0.32). The image quality scores for MR enterography examinations were significantly lower than those for CT enterography (p = 0.005). MR enterography and CT enterography identified eight cases (24%) with a final diagnosis of active small-bowel inflammation in which the ileal mucosa appeared normal at ileocolonoscopy. Furthermore, enterography provided the only available imaging in three additional patients who did not have ileal intubation. CONCLUSION MR enterography and CT enterography have similar sensitivities for detecting active small-bowel inflammation, but image quality across the study cohort was better with CT. Cross-sectional enterography provides complementary information to ileocolonoscopy.

Small-bowel imaging in Crohn's disease: a prospective, blinded, 4-way comparison trial

BACKGROUND With the introduction of new techniques to image the small bowel, there remains uncertainty about their role for diagnosing Crohns disease. OBJECTIVE To assess the sensitivity and specificity of capsule endoscopy (CE), CT enterography (CTE), ileocolonoscopy, and small-bowel follow-through (SBFT) in the diagnosis of small bowel Crohns disease. METHODS Prospective, blinded trial. SETTING Inflammatory bowel disease clinic at an academic medical center. PATIENTS Known or suspected Crohns disease. Exclusion criteria included known abdominal abscess and non-steroidal anti-inflammatory drug (NSAID) use. Partial small-bowel obstruction (PSBO) at CTE excluded patients from subsequent CE. INTERVENTIONS Patients underwent all 4 tests over a 4-day period. MAIN OUTCOME MEASUREMENTS Sensitivity, specificity, and accuracy of each test to detect active small-bowel Crohns disease. The criterion standard was a consensus diagnosis based upon clinical presentation and all 4 studies. RESULTS Forty-one CTE examinations were performed. Seven patients (17%) had an asymptomatic PSBO. Forty patients underwent colonoscopy, 38 had SBFT studies, and 28 had CE examinations. Small-bowel Crohns disease was active in 51%, absent in 42%, inactive in 5%, and suspicious in 2% of patients. The sensitivity of CE for detecting active small-bowel Crohns disease was 83%, not significantly higher than CTE (83%), ileocolonoscopy (74%), or SBFT (65%). However, the specificity of CE (53%) was significantly lower than the other tests (P < .05). One patient developed a transient PSBO due to CE, but no patients had retained capsules. LIMITATION Use of a consensus clinical diagnosis as the criterion standard-but this is how Crohns disease is diagnosed in practice. CONCLUSIONS The sensitivity of CE for active small-bowel Crohns disease was not significantly different from CTE, ileocolonoscopy, or SBFT. However, lower specificity and the need for preceding small-bowel radiography (due to the high frequency of asymptomatic PSBO) may limit the utility of CE as a first-line test for Crohns disease.

Magnetic resonance imaging of hepatic fibrosis: Emerging clinical applications†

Chronic liver disease and cirrhosis remains a major public health problem worldwide. While the majority of complications from chronic liver disease result from progressive hepatic fibrosis, the available diagnostic tests used in clinical practice are not sensitive or specific enough to detect occult liver injury at early or intermediate stages. While liver biopsy can stage the extent of fibrosis at diagnosis, its utility as a tool for longitudinal monitoring will be limited at the population level. To date, a number of methods including serum marker panels and ultrasound‐based transient elastrography have been proposed for the non‐invasive identification of hepatic fibrosis. Novel techniques including magnetic resonance (MR) spectroscopy, diffusion weighted MR, and MR elastography have also emerged for detecting fibrosis. In contrast to other non‐invasive methods, MR imaging holds the promise of providing functional and biological information about hepatic pathophysiology as it relates to the natural history and future treatment of hepatic fibrosis. (HEPATOLOGY 2007.)

Detection of flat lesions in the colon with CT colonography

AbstractBackground:We investigated whether flat lesions of the colon could be detected on computed tomographic colonography (CTC). Methods: CTC and conventional colonoscopy were performed on 547 consecutive patients. A subset of 22 polyps was described as flat on colonoscopy (n= 16) or CTC (n= 6) and are the basis of this report. CTC was performed with a standard technique (5-mm collimation, 3-mm reconstruction intervals). Patients were scanned in supine and prone positions. Examinations were randomly assigned and reviewed in a blinded fashion by two of three radiologists. Prospective interpretations were recorded. All patients had conventional colonoscopy, which served as the gold standard. Results: Twenty-two flat lesions ranging from 0.4 to 3.5 cm were histologically classified as adenomatous (n= 8) or hyperplastic (n= 14). The sensitivities for detecting all flat lesions and flat adenomas by each reviewer were 43% and 100%, 65% and 100%, and 15% and 13%, respectively. “Double reading” resulted in detection of 68% of all lesions and 100% of adenomas. Of the seven hyperplastic polyps missed by both reviewers, four were identified retrospectively. Conclusion: Flat lesions of the colon represent an important source of false negative CTC examinations. Awareness of their morphology can assist radiologists in finding most of these challenging lesions.

Obscure Gastrointestinal Bleeding: Evaluation with 64-Section Multiphase CT Enterography—Initial Experience

This retrospective HIPAA-compliant study was approved by the institutional review board and institutional conflict of interest committee. Patients gave informed consent for use of medical records. The purpose of the study was to retrospectively evaluate the findings depicted at computed tomographic (CT) enterography performed with a 64-section CT system and by using neutral enteric contrast material and a three-phase acquisition in patients with obscure gastrointestinal bleeding (OGIB). Twenty-two outpatients (11 men, 11 women; age range, 37-83 years) with OGIB underwent CT enterography. Findings were compared with capsule and traditional endoscopic, surgical, and angiographic findings. CT enterographic findings were positive for a bleeding source in 10 (45%) of 22 patients. Eight of 10 positive findings at CT enterography were also positive at capsule endoscopy or subsequent clinical diagnosis. CT enterography helped correctly identify three lesions undetected at capsule endoscopy. Study results suggest that multiphase, multiplanar CT enterography may have a role in the evaluation of OGIB.

ACG Clinical Guideline: Diagnosis and Management of Small Bowel Bleeding

Bleeding from the small intestine remains a relatively uncommon event, accounting for ~5–10% of all patients presenting with gastrointestinal (GI) bleeding. Given advances in small bowel imaging with video capsule endoscopy (VCE), deep enteroscopy, and radiographic imaging, the cause of bleeding in the small bowel can now be identified in most patients. The term small bowel bleeding is therefore proposed as a replacement for the previous classification of obscure GI bleeding (OGIB). We recommend that the term OGIB should be reserved for patients in whom a source of bleeding cannot be identified anywhere in the GI tract. A source of small bowel bleeding should be considered in patients with GI bleeding after performance of a normal upper and lower endoscopic examination. Second-look examinations using upper endoscopy, push enteroscopy, and/or colonoscopy can be performed if indicated before small bowel evaluation. VCE should be considered a first-line procedure for small bowel investigation. Any method of deep enteroscopy can be used when endoscopic evaluation and therapy are required. VCE should be performed before deep enteroscopy if there is no contraindication. Computed tomographic enterography should be performed in patients with suspected obstruction before VCE or after negative VCE examinations. When there is acute overt hemorrhage in the unstable patient, angiography should be performed emergently. In patients with occult hemorrhage or stable patients with active overt bleeding, multiphasic computed tomography should be performed after VCE or CTE to identify the source of bleeding and to guide further management. If a source of bleeding is identified in the small bowel that is associated with significant ongoing anemia and/or active bleeding, the patient should be managed with endoscopic therapy. Conservative management is recommended for patients without a source found after small bowel investigation, whereas repeat diagnostic investigations are recommended for patients with initial negative small bowel evaluations and ongoing overt or occult bleeding.

Small, nonfunctioning, asymptomatic pancreatic neuroendocrine tumors (PNETs): Role for nonoperative management

BACKGROUND Controversy exists regarding the optimal management of incidentally discovered, small pancreatic neuroendocrine tumors (PNETs). Our aim was to review the outcomes of patients who underwent nonoperative and operative management. METHODS We retrospectively reviewed patients with nonfunctioning PNETs at our institution from January 1, 2000 to June 30, 2011. Patients were included if the tumor was sporadic and <4 cm without radiographic evidence of local invasion or metastases. RESULTS Nonoperative patients (n = 77, median age, 67 years; range, 31-94) had a median tumor size of 1.0 cm (range, 0.3-3.2). Mean follow-up (F/U) was 45 months (max. 153 months). Median tumor size did not change throughout F/U; there was no disease progression or disease specific mortality. In the operative group (n = 56, median age, 60 years; range, 27-82), median neoplasm size was 1.8 cm (range, 0.5-3.6). Mean F/U was 52 months (max. 138 months). A total of 46% of the operative patients had some type of complication, more than half due to a clinically significant pancreatic leak. No recurrence or disease specific mortality was seen in the operative group, including 5 patients with positive lymph nodes. CONCLUSION Small nonfunctioning PNETs usually exhibit minimal or no growth over many years. Nonoperative management may be advocated when serial imaging demonstrates minimal or no growth without suspicious features.

Prospective Blinded Comparison of Wireless Capsule Endoscopy and Multiphase CT Enterography in Obscure Gastrointestinal Bleeding

PURPOSE To compare the performance of multiphase computed tomographic (CT) enterography with that of capsule endoscopy in a group of patients with obscure gastrointestinal bleeding (OGIB). MATERIALS AND METHODS This prospective HIPAA-compliant study was approved by the institutional review board and the institutional conflict of interest committee. All patients provided written informed consent. Two radiologists, blinded to clinical data and results of capsule endoscopy, interpreted images from CT enterography independently, with discordant interpretations resolved by consensus. Results were compared with those from a reference standard (surgery or endoscopy) and clinical follow-up. Sensitivity and 95% confidence intervals were calculated for each modality. RESULTS Fifty-eight adult patients, referred for the evaluation of OGIB (occult, 25 patients [43%]; overt, 33 patients [57%]), underwent both tests. A small bowel bleeding source was identified in 16 of the 58 patients (28%). The sensitivity of CT enterography was significantly greater than that of capsule endoscopy (88% [14 of 16 patients] vs 38% [six of 16 patients], respectively; P = .008), largely because it depicted more small bowel masses (100% [nine of nine patients] vs 33% [three of nine patients], respectively; P = .03). No additional small bowel tumors were discovered during the follow-up period (range, 5.6-45.9 months; mean, 16.6 months). CONCLUSION In this referral population, the sensitivity of CT enterography for detecting small bowel bleeding sources and small bowel masses was significantly greater than that of capsule endoscopy. On the basis of these findings, the addition of multiphase CT enterography to the routine diagnostic work-up of patients with OGIB should be considered, particularly in patients with negative findings at capsule endoscopy.

New Concepts in Intestinal Imaging for Inflammatory Bowel Diseases

In the last decade, multiple imaging technologies have been developed that improve visualization of the mucosal, mural, and perienteric inflammation associated with inflammatory bowel diseases. Whereas these technologies have traditionally been used to detect and stage suspected enteric inflammation, we review new, emerging roles in detecting clinically occult inflammation (in asymptomatic patients) and inflammatory complications, predicting response prior to therapy, assessing response after therapy, and enteric healing. We compare the relative performance of these technologies in detecting inflammation, focusing on their advantages and disadvantages and how they might complement each other. We also discuss their potential benefits for patients and clinical trials, reviewing technologic developments and areas of research that could provide important insights into the pathophysiology of inflammatory bowel diseases-related enteric inflammation.

Dual-phase CT of autoimmune pancreatitis: a multireader study.

OBJECTIVE The purpose of this study was to identify findings that aid in differentiating autoimmune pancreatitis from pancreatic carcinoma using dual-phase CT. MATERIALS AND METHODS Dual-phase CT scans of 74 patients (25 with autoimmune pancreatitis, 33 with pancreatic carcinoma, and 16 with a normal pancreas) were independently evaluated by three radiologists for enhancement of the pancreas; the presence of a capsule-like rim, peripancreatic strands, and pancreatic calcifications; pancreatic duct or bile duct changes; and renal involvement. The frequency of CT characteristics was compared between autoimmune pancreatitis and carcinoma. Interobserver agreement for the three reviewers for the assessment of CT characteristics was evaluated using kappa statistics. RESULTS Diffusely decreased enhancement of the pancreas (autoimmune pancreatitis vs carcinoma: 28% vs 3%; p = 0.02, kappa = 0.33-0.75), capsule-like rim (40% vs 9%; p = 0.009, kappa = 0.42-0.66), peripancreatic strands (60% vs 27%; p = 0.02, kappa = 0.45-0.54), pancreatic calcifications (32% vs 9%; p = 0.04, kappa = 0.14-0.47), bile duct wall enhancement (52% vs 6%; p = 0.0001, kappa = 0.28-0.47), and renal involvement (28% vs 0%; p = 0.002, kappa = 0.32-0.74) were more frequent in patients with autoimmune pancreatitis. Pancreatic duct dilation (24% vs 67%; p = 0.001, kappa = 0.65-0.73) and abrupt cutoff (16% vs 55%; p = 0.003, kappa = 0.60-0.65) were more frequent in patients with carcinoma. CONCLUSION Diffusely decreased enhancement of the pancreas, a capsule-like rim, bile duct enhancement, and renal involvement are useful signs of autoimmune pancreatitis.